Quantifying the differential functional behavior between the medial and lateral meniscus after posterior meniscus...

Area of Science:

• Orthopedics
• Biomechanics
• Knee Joint Anatomy

Background:

• Meniscus tears, especially posterior root tears, are common knee injuries.
• Current treatments for posterior meniscus root tears have limited healing rates and often result in persistent meniscal extrusion, failing to restore native function.
• Abnormal meniscal extrusion can lead to reduced knee function and accelerate osteoarthritis development.

Purpose of the Study:

• To investigate the distinct functional behaviors of the medial and lateral meniscus during axial compression and dynamic knee motion.
• To test the hypothesis that significant differences exist in meniscal extrusion between the medial and lateral meniscus under load and varying knee flexion angles.

Main Methods:

• Utilized a cadaveric model to simulate axial compression and dynamic knee motion.
• Quantified meniscus extrusion in response to posterior root detachment for both medial and lateral menisci.
• Analyzed extrusion at various knee flexion angles.

Main Results:

• No significant difference in extrusion was observed between medial and lateral menisci with an intact posterior root.
• Posterior root detachment led to substantially greater medial meniscus extrusion (2.233mm) compared to the lateral meniscus (0.4705mm).
• Medial meniscus extrusion increased across all flexion angles post-detachment, peaking at 30 degrees, while lateral meniscus extrusion peaked in extension.

Conclusions:

• The medial and lateral menisci exhibit differential functional responses to posterior root detachment.
• Medial meniscus extrusion is more pronounced and occurs dynamically during flexion after root detachment.
• Effective posterior root repair strategies must aim to minimize extrusion and replicate the unique native functions of each meniscus.